Tomb raiding in Egypt dates to antiquity; however, since the fall of former dictator Hosni Mubarak in 2011, the plunder appears to have become more widespread, and more professional.

The thieves are organized in gangs; some are armed and violent. The tomb sites were guarded well for decades but after Mubarak's ouster the once-feared police services simply melted away.

The elimination of the despised police services also left a security vacuum and an open invitation to trespass without fear of reprisal, archaeologists say.

They come every night, sometimes in groups of up to 40 and armed with machine guns, say custodians at the sites. They work with sophisticated equipment to move mounds of sand that have protected the dead for thousands of years.

Guards hired to protect the sites have not had success in trying to stop the looters; three were badly injured in confrontation two months ago.

"Since the revolution, the police don't want to do anything," says Sayeed Hussein, 32, a custodian at the site. "How am I supposed to approach an armed gang when none of us have weapons?"

Until 1996, the Dahshur necropolis was a closed military zone. It has never been properly surveyed. It was here that Pharaoh Sneferu commissioned the first of Egypt's classical pyramids, a forerunner of the more famous ones at Giza.

Archaeologists believe there are hundreds of ancient tombs waiting to be discovered here although none thought to be as grand as those in the Valley of the Kings near Luxor, where Pharaohs were buried in tombs crammed with gold.

The custodians say the looters get little of monetary value, turning up objects such as pieces of pottery, beads, perhaps a coffin. Hanna disagrees. She says that thieves have removed valuable statues from the tombs, and that even a small item can sell for about $600 on the black market.

In a country where many live on government handouts, $600 is a small fortune.

Theft is not the only danger to Egypt's ancient past.

Just a few hundred yards from the crumbling Black Pyramid, the burial site of Amenemhat III, dozens of villagers are building a new cemetery that encroaches on the necropolis. The markers for the new graveyard stretch to just a few yards from German excavations of an ancient temple.

Structures built as recently as just a few days ago are believed to sit above an ancient harbor that was part of the pyramid complex, and which archaeologists are eager to uncover. Villagers have ignored government orders to stop building, insisting that the state has provided them with no alternative but to expand toward the pyramids.

"Where can the people go? There isn't any other space," says Mitwali Abdul, 48, a rickshaw driver. "The government only says: 'Don't build there, don't build here.' "

Critics have accused Egypt's new Islamist government of indifference towards its pre-Islamic past, and say that national heritage is being destroyed in plain view, both by looters and illegal construction.

"Under Mubarak, (the pyramids) were seen as a revenue stream for tourism, and a point of pride," Hanna says. "This government just doesn't care."

Some Muslims consider the pyramids idolatrous and the product of a rotten civilization. A Salafist preacher recently advocated their destruction.

Kamal Wahid, an antiquities ministry official, denies official indifference. He says that the ministry lacks the financial resources to protect the site because of a drop-off in tourism revenue. He says reports of looting and damage are exaggerated, and that thieves often dig a few feet and abandon the holes before they find anything.

But activists say looting that was once erratic has now become sophisticated and it is satisfying a thriving demand in Europe for Egyptian antiquities smuggled out of the country.

Each piece taken out loses 70% of its history, says Hanna, who has been documenting the looting at Dahshur, a 4,500-year-old royal necropolis. "It is history for everyone that is being lost."